Tube-still control



Jan. 25, 1927. 1,615,481

F. M. POOLE TUBE STILL CONTROL Filed Jan. 2, 1926 Mantra! NIL on. LIN!INVENTOR Patented Jan. 25,, 19227.,

UNETEVD STATE.

a 1.615381 ear-eur- OFFIC;

FOSTER M. POOLE, OF TULSA OKLAHOIIMIA, ASSIGNOR TO THE BROWN INSTRUMENTCOMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENNSYL-Application filed January a, 1926. Serial No.

The general object of the present invention is to provide a simple andeffective method of and means for controllingcombustion conditions in anoil refining tube still in such manner as to secure the proper oilheating effect while maintaining efficient combustion. conditions in thestill furnace.

The invention is characterized by the fact that the general rate ofcombustion is made responsive to the heat requirements of the still, andthe ratio of fuel and combustion supporting air supplied to the furnaceis made dependent on the composition of the flue gases, and that thisresult is obtained with the use of simple and effectiveinstrumentalities which may be of standard commercial types. .lncarrying out my invention, T provide means for regulating the supply offuel to the still combustion chamber and provide other means forregulating the supply of combustion supporting an to said chamber, andprovide means for adjusting one of said supply regulating means inautomatic response to the changes in the vices; and

temperature to which theoil is heated, and provide means for adjustingthe other supply regulating means in response to changes in thecomposition of the flue gases leaving the furnace.

The various features of novelty which characterize my invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,however, its advantages and specific objects attained with its use,reference should be had to the accompanying drawings and descriptivematter in which l have illustrated and described preferred forms of apparatus for use in carrying out the invention.

@fthe drawings:

Fig. l is a diagrammatic representation of an oil refining tube stillrelating de- Fig. 2 is a view taken similarl to Fig. 1 showing a portionof a tube stil equipped with a modified form of regulating means; and

l 'ig. 3 is a diagraatic representation of the electrical connections ofthe gas analysis apparatus. e

In Fig. l l have diagraatically illustrated an embodiment of the presentinvention including a tube still A of conventional type. As shown thetube still A comprises a TUBE-STILL CONTL.

combustion chamber A beneath a bank of horizontal tubes B'which areswept by the heating gases passing from the combustion chamber A to thefurnace stack outlet A The tubes B are connected at their ends so thatthe oil passes successively through tubes B at successively lower levelsfrom an oil inlet B to an oil outlet B The oil to be refined is suppliedto the inlet B by a fuel pump C, which, in the preferred mode of usecontemplated by me, 1s operated to supply oil to the. still at aconstant rate.

Fluid fuel, which ordinarily is oil, is sup- )lied to the combustionchamber A through urner nozzlesD. The burner nozzles D receive fuel froma suitable pressure source (not shown) through a supply pipe D at a ratedepending on the adjustment of a fuel supply regulating valve D Air forcombustion is supplied to the combustion chambers! through supply pipesreceiving air from the outlet F of a blower F at a rate dependent on theadjustment of a blower regulator ll which, when the blower is turbinedriven as contemplated in the particular ,arran ement shown in Fig. 1,is a valve in t e pipe F supplying impelling steam to the blower.

In accordance with the present invention the valve D is adjusted toincrease and decrease the supply of fuel to the combustion chamber asthe temperature to which the oil is heated in passing through the tubesB falls below or rises above a predetermined temperature. This result isobtained. with the form of construction illustrated by means of areversible electric motor G energized for operation in one way toincrease the supply of fuel-and in the opposite direction to decreasethe supply'of fuel by means of a pyrometer controller H which isresponsive to the temperature to which a thermo-responsive device I issubjected. As shown the thermo-responsive device l is a thermo-coupleinserted in a thermometer well 13 in the path of oil flow at or adjacentthe still outlet B The terminals of the thermo-couple are connected byconductors 8 and 9 to corresponding terminals of the pyrometercontroller ll. .As shown, one

terminal of the motor'G is connected by a conductor 3 to the conductor 2of an electric current supply or power circuit. The contill troller Hoperates in response to the potential developed by the thermocouple I toconnect one terminal 6 of the motor G to the conductor 1 of the powercircuit through controller H connects a second terminal 5 of the 'motorGr to the conductor 4 and thereby to the supply conductor 1, and therebycauses the motor G to rotate in the direction to open or increase theflow through the valve D The pyrometer controller H may be of any usualor suitable form of instrument for the purpose. In general, it includesa voltmeter having its terminals connected by the thermo-couple I, andincludes a switch mechanism controlled by the voltmeter pointer andserving to connect the motor terminal 6 to the conductor 4. when the oiltemperature is above the predetermined value and to connect the motorterminal 5 to the conductor 4: when the oil temperature is below thepredetermined value. The switch mechanism in an instrument of this typeis ordinarily actuated by a motor or other relay which may be energizedfrom the supply conductors l and 2 through the conductors 6 and 7. Thave not thought it necessary to illustrate and describe in detail theconstruction of the pyrometer controller H, for the reason that thepresent invention does not depend on the specific form of the controllerand various forms of control instruments suitable for the purpose areknown. For example, the controller H may be of the type disclosed in thepatent to iFrown No. 1,355,44E8, granted October 12,

In accordance with the present invention the supply of air forcombustion to the combustion'chamber A to the furnace inlets E isregulated to maintain a desirable and approximately constant flue gascomposition. 11 the arrangement shown in Fig. 1, this regulation isobtained by means .of an electrical flue gas analyzing system includinga 00 controller HA which directly controls the motor GA to increase anddiminish the air su plied by the inlets .E accordingly as the C 2content of the flue gas falls below or rises above a predeterminedvalue. The

flue gas analyzing .means may be of an .usual or suitable type. Asdiagrammatical'ly illustrated, it is of the known type in which a smallstream offluegas iswithdrawn from the furnace adjacent the stack outletthrough a sample tube L, condenser M, filter and an electrical gasanalysis cell device K y an aspirator O in which water supplied by apipe P serves as the impelling fluid. As shown,- the pipe P passes waterinto the cooling water space of the condenser M, and the water passingfrom said space to the aspirator through a pipe P. In the known type ofgas analysis apparatus conventionally illustrated in Fig. 1, thediiterent thermal conductivities of the flue gas and of a standard orcomparison gas, which ordinarily is air, in cells of the device K, givedilterent temperatures and thereby diflerent resistance values toresistors forming a part of a suitably energized Wheatstone bridge. Inthe diagrammatic representation of Fig. 3, K represents the standard orcomparison cell containing a resistor r and air or other standard gas bywhich heat result ng from the current flow through the resistor r isconducted to the metal wall of the cell K. K is the test gas cell of thedevice K and has located in it a resistor r. The cells IQ and theresistor 1* may be identical with the cell K and the resistor 9" exceptthat the cell K is normally sealed after being filled with air or othercomparison gas, while the cell K is formed with ports K for the influx;and efiluzr of flue gases. The resistors 9 and 1" are connected into aWheatstone bridge of which they form two arms. The other two arms of thebridge are formed by so-called balance resistors R and R. K represents asource of current for energizing the Wheatstone bridge. The bridgepotential difference varied by temperature variations of said resistorsr and 1" is transmitted by the conductors and to the CO controller HA.The controller HA may be identical in construction and mode of operationwith the controller H, and operates the motor GA to increase anddecrease the su 1y of air in response to changes in the C6? content ofthe flue gases inexactly the same manner as the controller H operatesthe motor G in response to changes in the temperature of the oil towhich the thermocouple I is subjected. The connections between thecontroller HA, the motor GA, and the ower circuit conductors l and 2include con uctors 30, 40, 50, 60, and 70, corresponding respectively tothe conductors 3, 4, 5, 6, and 7.

In the normal intended operation of the apparatus shown in Fig. 1, oilis passed at 'a constant rate through the still tubes and is thereinheated to the desired final delivery temperature. The fuel is sup liedat the exact rate required to provide 1; e' necessary heating effect,and the air supply is regulated to insure. the desired .efliclency ofcombustion. The simple and eflective regulat ing provisions thus insurea uniform thermal efliciency which ma be the maximum practicallyobtainable. he actual thermal efliciency obtained will depend, ofcourse, upon conditions such as the character of the fuel burned, andthe weight of heating gases per' pound of fuel burned considered Iesirable in order to insure the desired rate of heat absorption bydifferent portions of the heat absorbing the surface, and the desirability of avoiding temperatures tending to local overheating of-anyportion of the tubes B- The rate at which the oil to be heated issupplied to the. tubes B depends on the speed of the ump C and'thelatter may be provided wit -h any suitable manual or automatic speedcontrol means. While I contemplate a nonfluctuating or constant oil feedto the tubes B,*the rate at which the oil to be heated is supplied maybe varied in response to changes in conditions, such as the progressivebuilding up of carbon deposits on the inner walls of *the tubes B whichoccurs between periods in which the latter are cleaned. w

Inlieu of controlling the composition of the flue gases by directlyregulating the air supplied to a furnace operated with forced draft, as,shown in Fig. 1, other means may I claim as'new and be employed tosecure the same control of the flue gas composition. For example, as

shown in Fig. 2, in a furnace operating with a stack draft, the stackdamper S: may be adjusted as through a belt R by a motor GA 7 controlledin the same manner as is the motor GA of Fig. 1.

Having now described my invention what desire to secure by Let tersPatent is: p

1. In heating oil to a refiningtemperature in a tube still, theimprovement whlch consists in maintaining an approximately constant oiltemperature at the still outlet by regulating the relative rates atwhich oil is passed through the tube still and at which fuel is burnedto heat the still in automatic response to said oil temperature, andmaintaining efiicient combustion conditions by fuel supplied at a ratevarying with the temperature to which the oil is heated as required tomaintain said temperature approximately constant and supplying air forthe combustion of the fuel as required to maintain an approximatelyconstant flue gas composition.

3. Anoil refining still comprising a combustion chamber, tubes heated bythe combustion of fuel supplied to said combustion chamber, meanspassing the oil to be refined through said tubes at a predeterminedrate, means responsive to the temperature at which the oil is heatedregulating the supply of fuel to said combustion chamber, and

means responsive to the coinpositionof the gaseous products ofcombustion formed in said combustion chamber regulating the supply ofcombustion supporting air to said combustion chamber.

Signed at Philadelphia, in the county of Philadelphia and State ofPennsylvania, this 28th day of December, A. D. 1925.

. FOSTER M. POOLE.

